Re: K/T revisited, was: Re: DINOSAUR digest 3382

[Phil Bigelow <bigelowp@juno.com>]

On Thu, 10 Nov 2005 21:06:58 -0200 Roberto Takata <rmtakata@gmail.com>
writes:

Jorge Dichenberg <jorgedich@yahoo.com>:
> > Isn't KT extinction easy? Perfectly selective for
> > feeding preferences. Everything which eats dead plants
> > (detritus) survived. Everything else died out.

> What about that survive/extinction pattern if we look at the marine
> biota? Sharks survived, marine reptiles don't.
> Ammonites go 
> extinct,
> squids don't.


Peter Ward (and others) believes that ammonites went extinct because they
bred/fed at shallow depths.  In contrast, he claims that nautaloids
survived because they bred/fed in deeper water.  I'm don't know what his
take is on squids and octopus.

The hypothesis is that the deeper depths were "buffered" from the carnage
that was occurring in the near-surface marine waters.  This idea is
supported by the observation that Maastrichtian benthic biota tended to
fare a little better than did their pelagic counterparts.

<pb>
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